(Joseph McAndrew Jr., being led into his preliminary hearing Friday at a district court in King of Prussia. Credit: Brad Segall)

KING OF PRUSSIA, Pa. (CBS) – A 23-year-old Upper Merion man has been ordered to stand trial on charges that he stabbed his mother, his father, and his twin brother to death in their King of Prussia home last March.

A Montgomery County detective testified today that when he questioned Joseph McAndrew Jr. about what happened the night his parents and brother were found dead in their home, he replied “extermination.”

When asked who, the detective recounted, McAndrew had replied eerily, “Person named father, person named mother, person named brother.”